Frequency and severity of sperm DNA damage in patients with confirmed cases of male infertility of different aetiologies

Men with high sperm DNA damage have a reduced fertility potential. Correlation of specific clinical factors to the degree of sperm DNA damage remains unclear. This retrospective study evaluated the frequency and severity of sperm DNA damage in men with different aetiologies of male factor infertility. Patients with male factor infertility (n = 288) underwent flow cytometry-based sperm DNA damage assessment and results were correlated with the major aetiologies of male infertility: varicocele, bacteriospermia and idiopathic infertility. Sperm DNA damage was significantly correlated to the patient’s age, sperm motility, normal morphology and vitality (P < 0.001). High sperm DNA damage (⩾30%) was most frequently found in the group with bacteriospermia (48%), compared with 30% of the men with varicoceles and 22% of the men with idiopathic infertility (P < 0.02). While some tendency was observed for a correlation of increasing sperm DNA damage in patients with grade III and bilateral varicoceles, this difference did not reach statistical significance. The data support the importance of proper physical and laboratory investigations of the fertility status in men to correctly diagnose and treat male infertility.